Trimming mechanism for sewing machines



Oct. 31, 1933. F. M. CARD TRIMMING MECHANISM FOR SEWING MACHINES Filed June 23, 1932 4 Sheets-Sheet l INVENTOR. 3 mm (2. BY.

A TTORNEYS.

Oct. 31, 1933. F. M. CARD TRIMMING MECHANISM FOR SEWING MACHINES Filed June 23, 1952 4 Sheets-Sheet 2 INVENTOR. 3 1 mm m A TTORVEYS Oct. 31, 1933. F CARD 1,932,953

TRIMMING MECHANISM FOR SEWING MACHINES Filed June 23, 1932 4 Sheets-Sheet 3 INVENTOR. 7 I 5% 714. 14,

/ A TTORNEYS.

Oct. 31, 1933. F. M. CARD TRIMMING MECHANISM FOR SEWING MACHINES Filed June 25, 1932 4 Sheets-Sheet 4 INVEN TOR. fwa 6 BY TTORN Patented Oct. 31, 1933 UNITED STATES TRIM'MIING MECHANISM FOR SEWING MACHINES Frederic M. Card, Bridgeport, Conn., assignor to The Singer Manufacturing Company, Elizabeth, N. J., a corporation of New Jersey Application June 23, 1932. Serial No. 618,882

4 Claims.

This invention relates to improvements in trimming mechanisms for sewing machines and has for its object to provide a trimmer actuating mechanism adapted for embodiment in a commercially Well known type of sewing mach nes, and more particularly in sewing machines having an alternating presser arrangement of upperfeeding mechanism.

The invention consists in the devices, combinations and arrangements of parts hereinafter described and claimed.

In the accompanying drawings, Fig. l represents a perspective view,.part1y in section, of a portion of a sewing machine containing a preferred embodiment of the present invention. Fig. 2 is a rear side elevation and Fig. 3 is a front end elevation of the machine. Fig. 4 is a top-plan view, partly in section of the free end portion of the machine bracket-arm. Fig. 5 is a cross-section of the bracket-arm substantially on the line 55 of Fig. 4.

Referring to the drawings, the sewing machine has a frame includinga horizontally disposed work-arm or cylinder 1 from which rises the standard 2 of a bracket-arm 3 terminating in a head 4 overhanging the work-arm '1.

Rotatably journaled in the bracket-arm 3 is :a main actuating shaft 5 to one end of which is secured a crank 6 connected by a link 7 with a needl -bar 8 journaled for vertical, reciprocation in a bushing 9 secured in the head 4. At its lower end, the needle-bar carries aneedle l0. Alsovertically movable insuitable bearings pro? vided in the head 4 is a spring-depressed presserbar 11 to the lower end of which is secured the shank of a presser-foot 12. Fixed upon the press- .er-bar is a fulcrum-block 13 pivotally supporting a bell-crank lever 14 of which one arm is connected by a link 15 with a crank-arm l5 rotatable with the needle-reciprocating crank 6. The other arm of the bell-crank lever is pivotally connected with the upper end of a feed-bar 17 carrying at its lower end a feeding-foot 18 having a serrated work-engaging face. The feedbar 17 is confined by a guide-plate 19 for sliding movements in a suitable slot in the bracketarm head 4 and is yieldingly urged by a spring 20 toswing forwardly. The described construction comprises a well known type of upper feeding mechanism in which the presser-foot and feeding foot reciprocally engage the work,'the

feeding foot 18 advancing with the work fed intermittently by a suitably actuated lower feeddog 21. When the presser-foot engages the work,

the feeding foot 18 is raised, whereupon the spring 20 retracts the feed-bar in the usual manner.

The present invention resides more particularly in an improved trimming mechanism carried by a supporting bracket 22 detachably seciued by screw-bolts 23 upon a fiatseat provided at the under side of the machine bracketarm3. At its free end, the bracket 22 has vertically spaced lugs 24 provided with vertically alined slots 25 substantially parallel with a vertical plane containing the axis of rotation of the main-shaft 5. The slots 25 are closed at their outer ends by guide-plates 26, suitably secured upon the lugs 24; thereby providing alined guideways in which is slidably fitted a flat sided trim- 7 (l mer-blacle carrier 2'7. Intermediate its ends, the carrier 27 has a horizontal projection 28 provided in its front face with a grooved guideway 29 in which the upper end of a trimmer-blade holder 30 is secured by screws 31 for adjustment crosswise of the line of seam formation. Fastened, byscrews 32 upon the holder 30, is the vertically slotted upper end of a trimmer blade 33 having a reciprocatory path of movement closely adjacent'to the presser-foot 12 to sever the work on a line parallel with the line of seam formation.

A finger-piece 3 4 projecting forwardly from the holder 30 is formed as a separate member secured to said holder. by the screws 31.

The trimmer-blade carrier 27 is provided with 8 ahorizontal'guideway 35 disposed transverse to the guideway 29 and substantially parallel with the line of seam formation, in which guideway is slidably fittedva guide-block 36 suitably apertured to receive the rounded end 3'? of one arm of a lever pivotally supported intermediate its ends by a fulcrum-stud 38 upon 2. lug 39 at the rear side of the bracket 22. The other arm 40 of said lever is connected to the lower end of a link 41 of which the upper end is pivotally connected by a screwbolt 42 to a latch-member 43. The latch-member 43 has a hub 44 secured by a set-screw 45 upon one end of a sleeve 46 journaled for rocking movements in a bearing lug 4'7 provided upon the rear side of the bracket-arm 3. A flange 48 on the sleeve 46 holds the latter against endwise movement in one direction in the h1g4? and the latch-member hub 44 holds said sleeve against movement in the opposite direction.

The sleeve 46 is apertured longitudinally to slidingly receive a rock-shaft 49 of which one end is additionally supported by a bearing lug 50 upon the bracket-arm head 4. Suitably fastened upon the rock-shaft 49, between the bracket-arm lug 50 and the latch-member hub 44, is a latchno arm 51 carrying at its free end a latch-pin 52 adapted to enter a notch 53 provided in the latchmember 43. Rocking movements are imparted to the rock-shaft 49 by an actuating arm 54 of which one end is suitably secured upon the rockshaft adjacent to the sleeve-flange 48 and the other end is forked to straddle an eccentric 55 upon the main shaft 5.

In order to manually shift the rock-shaft 49 endwise in its hearings to connect and disconnect the latch-pin 52 and latch-member 43, said rockshaft is provided with an annular groove 56 straddled by a forked car 57 formed upon one arm 58 of an angular hand-lever 58, 59 pivotally supported intermediate its ends upon the machine bracket-arm by a fulcrum-studfiO. The lever-arm 59 overhangs a boss 61 upon the bracket-arm 3, which boss is socketed to receive a coil-spring 62 engaging the under side of the lever-arm 59 to urge the rock-shaft endwisein a direction to effect engagement of the latch-pin 52 with the latch-member 43. The lever arm 58 curves forwardly under the bracket-arm 3 for convenient manipulation by the machine operator. A coil spring 63 has one end connected with the screwbolt 42 upon the latch-member 43, the other end of said spring being suitably anchored to the bracket-lug 39. The eccentric 55 is elongated sufficiently to retain the forked arm 54 in engagement therewith when the rockshaft 49 is shifted endwise and accordingly the latch-member 43 is continuously actuated during the operation of the machine.

It will be readily understood from the foregoing description that when the rock-shaft 49 is operatively connected with the latch-member 43, the trimmer-blade will be vertically reciprocated during the operation of the machine. To discontinue trimming, the operator swings the handlever arm 58 toward the bracket-arm head 4, thereby sliding the rock-shaft 49 endwlse in a direction to withdraw the latch-pin 52 from the latch-member notch'53. The spring 63 is thereupon free to swing the latch-member 43 downwardly, causing a corresponding downward movement of the link 41 and consequently an upward movement of the trimmer-blade carrier 27 into an inoperative position determined in the present instance by a stop-pin 64 depending from the upper of the bracket-lugs 24 and engaged by the carrier. To again bring the trimmer into operation, a downward pressure upon the finger-piece 34 shifts the latch-member 43 upwardly until the notch53 thereof is in alinement with the latchpin 52, whereupon the spring 62 functions to again seat the pin in the notch of the continuously actuated latch-member 43. 7

Having thus set forth the nature of the invention, what I claim herein is:

1. In a sewing machine having a frame including a work-support and a bracket-arm overhanging the work-support, stitch-forming mechanism including a vertically reciprocatory needle, work-feeding mechanism, a trimmer-bracket detachably secured to said bracket-arm having vertically spaced lugs provided with vertically alined guideways, a trimmer-blade carrier slidably disposed in said guideways for vertical reciprocation, said trimmer-blade carrier having horizontally disposed transverse guideways, a trimmer-blade holder secured in one of said carrier guideways for adjustment crosswise of the direction of feed, a trimmer-blade carried by said holder, a slide-block disposed in the other of said carrier guideways, a lever fulcrumed upon said trimmer-bracket having one arm connected with said slide-block, and actuating mechanism operatively connected with the other arm of said lever for reciprocating said trimmer-blade carrier.

2. In a sewing machine having a frame including a work-support and a bracket-arm overhanging the work-support, stitch-forming mechanism, work-feeding mechanism, a trimmer bracket detachably secured to said bracket-arm having vertically spaced lugs provided with vertically alined guideways, a trimmer-blade carrier slidably disposed in said guideways for vertical reciprocation and having horizontally disposed transverse guideways between said trimmer-bracket lugs, a trimmer-blade holder adjustably secured in one of said carrier guideways, a slide-block disposed in the other of said carrier guideways, a lever fulcrumed upon said trimmer-bracket having one arm connected with said slide-block, and actuating mechanism connected with said lever for reciprocating said trimmer-blade carrier including means manually operable at will for disconnecting said trimmer-carrier from said actuating mechanism.

3. In a sewing machine having a frame including a work-support and a bracket-arm overhanging the work-support, a rotary actuating shaft journaled in said bracket-arm, a sleeve rotatably journaled upon said bracket-arm and having a shaft-bearing aperture, a rock-shaft disposed substantially parallel with said actuating shaft and journaled in said sleeve, connections for rocking said rock-shaft from said actuating shaft, a latch-member carried by said sleeve, a latch-arm carried by said rock-shaft operatively engaging said latch-member, a vertically reciprocatory trimmer-blade carrier, operative connections between said carrier and said latchmember for reciprocating the carrier, and manually operable means for shifting said rock-shaft endwise to disconnect the latch-member and latch-arm.

.7 4. In a sewing machine having a frame including a work-support and a bracket-arm overhanging the work-support, a trimmer-bracket secured to said bracket-arm and provided with a vertical guideway, a trimmer-blade carrier slidably disposed in said guideway for vertical reciprocation, a horizontally disposed rock-shaft journaled upon said bracket-arm, a sleeve journaled upon'said bracket-arm for rocking movements about an axis concentric with the axis of said rock-shaft, a latch-member carried by said sleeve, a latch-arm carried by said rock-shaft for engagement with said latch-member, a lever fulcrumed upon said trimmer-bracket and operatively connected with said trimmer-bladecarrier, a link connecting said latch-member to said lever, means for actuating said rock-shaft in the latch-member engaging position of said latch-arm to thereby reciprocate said trimmerblade carrier, manually operable means for shifting said rock-shaft endwise to thereby disconnect said latch-member and latch-arm, and a spring acting to raise said trimmer-blade carrier into inoperative position upon disconnection of said latch-arm and latch-member.

' FREDERIC M. CARD. 

